Title:
METHOD AND APPARATUS FOR INDEPENDENTLY CONTROLLING EACH PHASE OF A MULTI-PHASE STEP MOTOR
Document Type and Number:
WIPO Patent Application WO2005013474
Kind Code:
A3
Abstract:
The current in each phase of a multi-phase step motor (9) is monitored and the excess phase current above the set point current, as required on a cycle-by-cycle PWM basis, is reduced thereby bringing each phase current down to the set point. The PWM frequency is automatically adjusted to maintain a minimum number of PWM edges within a portion of the current waveform. A maximum charge/discharge time is specified as a percentage of the PWM period. These provide an accurate independent current control within each phase of a multiphase step motor (9).
Inventors:
COUTU DAVID
FOURNIER ROBERT A
FOURNIER ROBERT A
Application Number:
PCT/US2004/023942
Publication Date:
August 11, 2005
Filing Date:
July 27, 2004
Export Citation:
Assignee:
INTELLIGENT MOTION SYSTEMS INC (US)
International Classes:
G05B19/40; H02P8/12; H02P; (IPC1-7): G05B19/40
Foreign References:
| US5650705A | 1997-07-22 | |||
| US5343382A | 1994-08-30 | |||
| US5886484A | 1999-03-23 | |||
| US6049184A | 2000-04-11 | |||
| US5952856A | 1999-09-14 | |||
| US4984647A | 1991-01-15 | |||
| US5457364A | 1995-10-10 | |||
| US5818178A | 1998-10-06 |
Other References:
See also references of EP 1658537A4
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